Hi! > >> > Also, please observe that if there is a mechanism allowing us to put individual > >> > devices, or entire subsystems (such as a bus with devices attached to it), into > >> > low power states at run time, without placing the entire system in a sleep > >> > state, and put them back into the full power state as needed, we won't need > >> > anything like the "early suspend" introduced by this series of patches. > >> > >> While early-suspend is not needed, it is still convenient on an > >> embedded device where some drivers are clearly only used when the > >> screen is on. > > > > Ah, that's interesting. So in fact you want some devices to go into low power > > states as soon as the screen is off and that's why you fint the early-suspend > > useful. Is this correct? > > Yes. We turn off the touchscreen and trackball when the screen turns > off since both these devices use additional power when enabled. > Neither of these devices can be turned off (after a timeout) while the > screen is on. Ok, first: It is not at all clear to me that trackball / touchscreen is unusable with screen off. For weird cases (using android to remotely control PC?) screen-off trackball-on makes sense. Actually... if you are charging than maybe waking up the device by touching the screen is a good idea? So maybe you are putting a bit too much policy into kernel. OTOH, as long as you do it in android-specific code, that's probably okay. So lets assume that trackball is unusable with screen off. Stuff is easy, then either 1) make your useland close trackball/touchscreen devices when they turn the screen off. (This is actually preffered, as it keeps policy out of the kernel) or 2) Just use notifier chain to notify trackball/touchscreen when the screen is going off. Pavel -- (english) http://www.livejournal.com/~pavelmachek (cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html _______________________________________________ linux-pm mailing list linux-pm@xxxxxxxxxxxxxxxxxxxxxxxxxx https://lists.linux-foundation.org/mailman/listinfo/linux-pm
